Related Experiment Video
Updated: Jun 21, 2026

In Vitro Chemical Mapping of G-Quadruplex DNA Structures by Bis-3-Chloropiperidines
Published on: May 12, 2023
An experimental and theoretical core-level study of tautomerism in guanine
Oksana Plekan1, Vitaliy Feyer, Robert Richter
1Sincrotrone Trieste, in Area Science Park, I-34012 Basovizza (Trieste), Italy.
Abstract:
The core level photoemission and near edge X-ray photoabsorption spectra of guanine in the gas phase have been measured and the results interpreted with the aid of high level ab initio calculations. Tautomers are clearly identified spectroscopically, and their relative free energies and Boltzmann populations at the temperature of the experiment (600 K) have been calculated and compared with the experimental results and with previous calculations. We obtain good agreement between experiment and the Boltzmann weighted theoretical photoemission spectra, which allows a quantitative determination of the ratio of oxo to hydroxy tautomer populations. For the photoabsorption spectra, good agreement is found for the C 1s and O 1s spectra but only fair agreement for the N 1s edge.
Related Concept Videos
DNA Base Pairing
DNA Base Pairing
Isomerism
Structural Isomerism
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
Nucleic Acid Structure
DNA Structure
DNA has a double-helix structure. The...
Stereoisomerism of Cyclic Compounds

